Numerical studies on orthokinetic agglomeration in a turbulent channel flow and in a stirred tank are presented. By using a lattice Boltzmann scheme to simulate the turbulent flow field, and a Monte Carlo algorithm to solve the particle size distribution, the dependence of the agglomeration rate on the sheer rate and the turbulent transport of particles is investigated. It is found that local Row information is needed to model agglomeration and that a description in terms of a volume-averaged agglomeration rate constant So is inadequate for both geometries. Furthermore. turbulent transport of particles is found to be an important factor in the overall agglomeration rate.